Here are links to resources that will help solidify and augment your understanding of the topics covered in the ArcGIS for Server: Site Configuration and Administration course. They are organized into the themes explored, though some of the resources are applicable to more than one theme:
1. Planning an ArcGIS Server site
2. Deploying an ArcGIS Server site
4. Integrating a web server
1. Planning an ArcGIS Server site
3. Controlling access to ArcGIS Server
9. Securing services
10. Securing the ArcGIS Server site
11. Site backup and recovery
1. Planning an ArcGIS Server site
5. Managing service resources
6. Configuring service capabilities
1. Planning an ArcGIS Server site
5. Managing service resources
6. Tuning services and troubleshooting issues
8. Creating and updating caches
12. Building multi-node sites
1. Planning an ArcGIS Server site
2. Deploying an ArcGIS Server site
4. Integrating a web server
12. Building multi-node sites
13. Implementing ArcGIS Server